Intelligent boom control with a hydraulic straight-line system for a feller buncher

1 . An intelligent boom control hydraulic system for a feller buncher having a hoist boom and a stick boom coupled to the hoist boom, the intelligent boom control hydraulic system comprising:

a hoist hydraulic cylinder for raising and lowering the hoist boom, the hoist hydraulic cylinder having a rod end and a base end;

a stick hydraulic cylinder for raising and lowering the stick boom, the stick hydraulic cylinder having a rod end and base end;

a hoist boom position sensor providing hoist boom position readings;

a stick boom position sensor providing stick boom position readings;

a hydraulic fluid pump;

a hydraulic reservoir including hydraulic fluid;

a hoist control valve controlling flow from the hydraulic pump to the base end of the hoist hydraulic cylinder, and controlling flow from the rod end of the hoist hydraulic cylinder to the hydraulic reservoir;

a stick control valve controlling flow from the hydraulic pump to the base end of the stick hydraulic cylinder, and controlling flow from the rod end of the stick hydraulic cylinder to the hydraulic reservoir;

a straight-line control valve for coupling the rod end of the hoist hydraulic cylinder and the rod end of the stick hydraulic cylinder;

an operator input device for input of an operator commands; and

a controller comprising a microprocessor and memory, the controller being in communication with the operator input device, the hoist boom position sensor, and the stick boom position sensor, the controller being operable to:

determine a target hoist boom velocity and a target stick boom velocity based on the operator commands, the hoist boom position readings, and the stick boom position readings;

access a look up chart stored in the memory, the lookup chart mapping valve combinations of the target hoist boom velocity and the target stick boom velocity to discrete valve-activation combinations corresponding to the hoist control valve, the stick control valve, and the straight-line control valve; and

control the hoist control valve, the stick control valve, and the straight-line control valve in accordance with the selected valve-activation combination from the lookup chart,

wherein the controller controls the valves such that no more than two of the hoist control valve, the stick control valve, and the straight-line control valve are simultaneously active during any operation, and

wherein the selected valve-activation combinations move a boom tip along a substantially straight path relative to a machine frame of the feller buncher.

2 . The intelligent boom control hydraulic system of claim 1 , wherein the hoist boom position sensor comprises a hoist cylinder position sensor determining a length of the hoist hydraulic cylinder.

3 . The intelligent boom control hydraulic system of claim 1 , wherein the stick boom position comprises a stick cylinder position sensor determining a length of the stick hydraulic cylinder.

4 . The intelligent boom control hydraulic system of claim 1 , further comprises a counterbalance valve with a first port controlling flow to the rod end of the stick hydraulic cylinder and a second port controlling flow to the rod end of the hoist hydraulic cylinder.

5 . The intelligent boom control hydraulic system of claim 4 , further comprising a straight-line activation for selectively actuating the straight-line control valve and the counterbalance valve to enable movement of the boom tip in a generally horizontal path.

6 . The intelligent boom control hydraulic system of claim 4 , wherein, when retracting the target hoist boom velocity indicates retraction of the hoist hydraulic cylinder and the target stick boom velocity indicates extension of the stick hydraulic cylinder simultaneously, the controller selects a valve-activation combination that activates the straight-line and the hoist control valve, thereby allowing hydraulic fluid to flow from the base end of the hoist hydraulic cylinder to the base end of the stick hydraulic cylinder through the counterbalance valve.

7 . The intelligent boom control hydraulic system of claim 4 , wherein, when the target stick boom velocity indicates retraction the stick hydraulic cylinder and the target hoist boom velocity indicates extension extension of the hoist hydraulic cylinder simultaneously, the controller selects a valve-activation combination that activates the straight-line control valve and the stick control valve, thereby allowing hydraulic fluid to flow from the base end of the stick hydraulic cylinder to the base end of the hoist hydraulic cylinder through the counterbalance valve.

8 . The intelligent boom control hydraulic system of claim 1 , wherein the operator commands comprise:

a first command from a first operator input device and a second command from a second operator input device, the first command enabling an operator to move the boom tip in a vertical direction, and the second command enabling the operator to move the boom tip in a generally horizontal path.

9 . The intelligent boom control hydraulic system of claim 1 , wherein when the target hoist boom velocity and the target stick boom velocity indicate simultaneous extension of the hoist hydraulic cylinder and the stick hydraulic cylinder, the controller then selects a valve-activation combination that activates the hoist control valve and the stick control valve while the straight-line control valve remains inactive.

10 . The intelligent boom control hydraulic system of claim 1 , wherein when the target hoist boom velocity and the target stick boom velocity indicate simultaneous retraction of the hoist hydraulic cylinder and the stick hydraulic cylinder, the controller selects a valve-activation combination that activates the hoist control valve and the stick control valve while the straight-line control valve remains inactive.